Anthraquinone-1-aldehydes and process of making same



Patented Aug. 21, 1934 ferries- ANTHRAQUINoNE-LALDEHYDES' PROCESS OF MAKING SAME fltto Bayer, Frankfort-on-the-Main, Germany, igncr to General; Aniline Works, Inc., New

:York, .N.' 56., a corporation of Delaware No Drawing. Application May 12, 1931, Serial No. 536,933; In GermanyJune 4, 1930 6 Claims.

"My present inventionrelates to anthraquinonel-aldehydes and to a process of making same.

The process of this invention comprises acting with an oxidizing agent ofthegroup consisting of oxides and salts of triand tetravalent manganese and lead on l-methyl-anthraquinone which may be substituted in themucleus in the presence of a sulfuric acid of -90% strength at a temperature ranging from 0-80. The diluent of the sulfuric .acid usedmay be watenglacial acetic acid or another suitable solvent. p,

.The'quantity of the oxidizing agent used-may be varied within fairly wide limits. It'is advisable to ascertain the optimum amount by a previoustest, since the brands for-example of manganic peroxide of different origin have quite a difierent effect. By the action of an excess of oxidizing agent, the anthraquinone-l-aldehyde compounds can be easily transformed into the corresponding carboxylic=acids (see French Patent 456,768, ExampleSl.

In this manner antraquinone-l-aldehydes are obtained with a good yield whereas the manufacture of these compounds hitherto involved such difliculties that the simplest representative of this series, i. e. anthraquinone-l-aldehyde itself,-has not yetbeen described in literature. By the oxidation of l -methyl-anthraquinone bimolecular compounds were obtained (see German Patent No. 481,291). Also by oxidizing-4- chloro-l-methylanthraquinone (see French Patent No. 4563768) only a "small yield of the aldehyde could heretofore be produced.

The anthraquinone-l-aldehyde and its nuclear substitution products which are obtained by my process are mainly unknown hitherto. They represent valuable intermediates for the production of dyestuffs. They are distinguished by the intense blue color which appears by heating the solution in glacial acetic acid with a drop of aniline, and by the reddish coloration of the products obtained on exposure to light.

In order to further illustrate my invention the following examples are given, the parts being by weight and all temperatures in centrigrade degrees, but it is however to be understood, that my invention is not limited to the particular products nor reacting conditions mentioned therein.

Example 1 50 parts of l-methyl-anthraquinone are dissolved at 50 in 900 parts of 84% sulfuric acid. Thereto a paste of 90-100 parts of artificial pyrolusite ofabout strength and 1000 parts of -83% sulfuric acid is added during 2 hours while stirring, the .ztemperaturetbeing maintained at 55465" :by xtempararysecoling. The .icolor emf the oxidation mass .rernazins 1ight yellow -(inccon;

tradi-stinction i130 the process of iGerman -:P.atent meltsat T834 Itformsa reddi'sh -brownvat and alight yellowsulfuric acid solution.

The process may likewise 'be-carried outat temperature or by replacing pyrolusiteby manganic sulfate/lead peroxide or lead tetracetate.

Example 2 160 parts of 4-chloro-l methyl-anthraquinon'e are --d-issol-ved in'a mixture *of 1 700 parted-96% sulfuric acid, 180 parts o'f glacial acetic acid :and "parts OfV/BitGI'. Intothi's solution parts of pyrol-us'ite -of 75% strength'which'aremade-up to a paste with the same quantity of the aforesaid mixture of sulfuric acid, acetic acid and water are introduced at about 40-50 during 2 hours while stirring. When the whole amount of pyrolusite has been disappeared the light yellow reaction mass is poured while stirring into water which is advantageously mixed with l part of bisulfite solution. The raw product forming colorless flakes is filtered and washed until being free from acid. By digesting it with a dilute solution of sodium carbonate its content of -chloroanthraquinone-l-carboxylic acid (about 15-20 is removed. In this manner nearly pure i-chloroanthraquinone-l-aldehyde of the. formula (I) C-HO is obtained. It melts when recrystallized from glacial acetic acid or from xylene at 216. By increasing the amount of acetic acid the concentration of sulfuric acid may be diminished until about 50% without influencing the course of reaction.

Exdmple 3 CEO is obtained which melts at 180 and shows other- 1 wise similar properties as the product of Example 1;

By using in this case an excess of the oxidizing agentthere are produced 4-methyl-anthraquinone-l-carboxylic acid, anthraquinone-i-aldehyde-l-carboxylic acid and anthraquinonelA-dicarboxylic acid.

By starting from 1.3-dimethyl-anthraquinone 3-methyl-anthraquinone-l-aldehyde is produced which yields on further oxidation 3-methylanthraquinone-l-carboxylicacid.

- I claim:

- 1. A' process forthe manufacture of anthraquinone-l-aldehydes which comprises acting with arr-oxidizing agent of the group consisting of oxides and salts of triand tetravalent manganese and lead on l-methyl-anthraquinone which may contain in 3 or ii-position a further methyl group in the presence of a sulfuric acid of 50-90% strength at a temperature ranging from 0-80" a quantity of oxidizing agent being employed which is proved by a test to give about two atomic proportions of active oxygen;

2. A process for the manufacture of anthraquinone-l-aldehyde which comprises acting with manganic peroxide on l-methyl-anthraquin-one in the presence of sulfuric acid of 75-90% strength at a temperature ranging from 40-80 a quantity of oxidizing agent being employed which is proved by a test to give about two atomic proportions of active oxygen.

3. A process for the manufacture of l-methylanthraquinone-1-aldehyde which comprises acting with manganic peroxide .on lA-dimethylanthraquinone in the presence of sulfuric acid of 75-90% strength at a temperature ranging from hydrogen or a methyl-group) which compounds are distinguished by the intense blue color which 40-80" a quantity of oxidizing agent being employed which is proved by a test to give about two atomic proportions of active oxygen.

4. As new compounds the anthraquinone-laldehydes of the general formula (wherein one X means hydrogen, the other X appears by heating the solution in glacial acetic acid with a drop of aniline and by the reddish coloration of the products obtained on exposure to light.

v 5. As a new compound the anthraquinone-laldehyde of the formula a 0 CH0 which compound melts at 180, forms a reddish brown vat and light yellow sulfuric acid solution and is distinguished by the intense blue color which appears by heating the solution in glacial acetic acid with a drop of aniline and by the reddish coloration of the product obtained on exposure to light. OTTO BAYER. 

